Midterm Flashcards
(175 cards)
1
Q
Define Propagation:
A
plant multiplication by sexual (seed) or asexual (vegetative) means.
2
Q
Define Clone:
A
a genetically uniform assemblage of individuals derived from a single individual by asexual propagation
3
Q
Define Domesticate:
A
Under human selection
4
Q
Define Inbreeding:
A
the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically.
5
Q
Define Wildtype:
A
the phenotype of the typical form of a species as it occurs in nature
6
Q
Define Cultivation:
A
the action of growing domesticate plant
7
Q
What are general aspects of propagation?
A
- Agriculture relies on knowledge of how to propagate plants.
- People went from hunters and gatherers to growers and farmers.
- In those areas the native plants were the first ones grown (some obtained from close-by areas or through trade)
8
Q
Briefly: How Plant Propagation Evolved in Human Society?
A
- Human has domesticated plants.
- First crop to be propagated was cereals and legumes because are seed-propagated.
- Other species not able to grow by seed so clone it.
- Then budding and grafting technique for fruit trees and rosaceous
- Then greenhouse permit leafy cuttings.
9
Q
What are characteristics of successful propagator?
A
- Master technical skills
- Understand plant structure and growth processes
- Acquire a knowledge of plants and the appropriate propagation techniques for each one.
10
Q
Describe Plant Nursery:
A
An area where plants are raised for eventual planting
11
Q
Describe Nursery land:
A
a parcel of land that serve as nursery.
12
Q
Describe Mother plant:
A
It provide bud sticks and scions for budding and grafting operations. Pests and diseases are controlled regularly by spraying pesticides and fungicides. Reproductive growth is strictly avoided. Only vegetative growth is permitted.
13
Q
Describe Administration Area:
A
Generally the office and the storage area occupy the same building with the exception of fuels and other inflammable or toxic materials.
14
Q
Describe Operation area:
A
Sufficient space should be provided to accommodate the following operations:
- Extracting, drying and processing of seed
- Preparing germination trays and potting mixtures
- Shed with compartments for screened soil, sand and compost
- Composting area
15
Q
Describe Production area:
A
Germination and transplanting Sections
- set up for germinating seeds and it is best to locate near the office, to enable the supervisors to maintain a close attention on the activities.
16
Q
Describe Nursey soil:
A
soil that will be used to grow new plants in the nursery. It can be field soil which a fertile and well drained soil. It can also be container soil which is used for plant in pots and need to be well drained. And greenhouse soil which consists of a growing media with a lot of aeration and good drainage.
17
Q
What is plant nursey? Why it is important in propagation?
A
- An area where plants are raised for eventual planting
- It consists of nursery beds, protected houses, paths, irrigation channels, etc.
18
Q
What are the purposes of constructing Nurseries?
A
- Providing suitable environment conditions for propagation.
- Controlling and protecting plants (disease, insect)
- Providing care to plants
- Start seedlings for next season
19
Q
List types of nurseries in terms of purpose and use
A
- Retail nurseries: sell to the general public.
- Wholesale nurseries: sell only to businesses
- Private nurseries: supply the needs of institutions or private estates.
- Mail Order Nurseries
20
Q
List types of nurseries in terms of specialty and production of agricultural crops
A
- Vegetable nurseries: specialist of vegetable seedlings.
- Ornamental plant nurseries: specialist of ornamental and flowering plants.
- Fruit tree nurseries: specialists in grafts, cuttings, scions for propagation purposes.
- Forest nurseries: propagate forest tree seedlings, which are used in parks and forestation.
- Medicinal and Aromatic Plant Nurseries + Hi-Tech Nurseries
21
Q
What are the conditions of establishing plant nurseries?
A
- Land: good drainage (soil aeration)
- Irrigation: good permanent source of water
- Access: near transportation roads
- Keep away from affected land and agriculture residue
- If land nursery: should be fenced with wind breaks.
22
Q
What are the roles of nurseries in forest development?
A
- Production of genetically pure stocks
- Export of nursery stocks
- Employment generation
- Role of nurseries in establishing forests and parks
23
Q
What are the criteria for selecting mother plants?
A
- vigorous, healthy and high yielded. It should have a regular bearing habit.
- free from pests, diseases and viruses.
- genetically pure and superior in quality.
- obtained from Registered Farms, Agriculture Universities or Government Nurseries.
- correspond to the regional demand of the nursery plants.
24
Q
What are the most important two physical sources of nurseries?
A
- Land and mother plant
25
What are types of nursery soils?
- Field: produce ornamental shrubs, fruit trees and perennial flowering plants. The soil should adhere to the roots of the plants well when the seedling are transplanted. Enriched top soil with compost and manure.
- Container: grow plants in containers. Used to grow trees or large shrubs. Smaller plants and shrubs are grown in pots above the ground. Pot mixture: sand, peat moss and hardwood bark. Can add nutrients and mineral. Balancing pH with lime is important.
- Greenhouse: Uses a combination of growing media. Aeration and drainage important. Sand and organic growth media such as hammered bark, compost, and sphagnum peat moss provide good support for young plants without exposing them to the disease and pest risks found in the soil.
26
Define Greenhouse:
is a structure with walls and roof made of transparent material, in which plants requiring regulated climatic conditions are grown.
27
Define Plastic house:
it is a greenhouse which the material covering it is plastic.
28
Define Lath house:
Reduce summer light levels, high temperatures, moisture stress, water requirements during summer. Roof is designed to cut light by 30-50%, depending on crop needs.
29
Define Cold frame:
No bottom heat. Warmed by the sun during the day. Used for hardening plants prior to field planting. Starting cuttings or seeds when no external heat is needed. Ventilation and shading (sometimes misting).
30
Define Hot bed:
Small, low structures. Bottom heat (thermostatically controlled). Sloping glass or plastic covers. Used for establishing cuttings or seedlings. Used all year' round except in severe winter areas (like here). Netting or wiring is used to cover the heating elements followed by a layer of substrate.
31
Define Microclimate:
light, water, relative humidity (RH), temperature, gases. Particularly important during the beginning of the plant’s life (eg: source plants or plants, during or production).
32
Define Edaphic:
related to the substrate eg: potting mixture components.
33
Define Biotic:
living aspects: fungi, bacteria, insects.
34
Define Plug production:
a seedling produced in a small volume of medium contained in a small cell.
35
Define Pasteurization:
moist and heating potting mixture to kill pathogens
36
Define Fumigation:
completely fills an area with gaseous pesticides—or fumigants—to suffocate or poison the pests.
37
Define Sanitation:
Remove all plant debris. Clean all equipment. Bleach, disinfectants for benches and tools. Copper naphthenate 2% solution for wood.
38
Define Soil Media:
Clay, loam, clay loam and sandy loam are examples for soil media.
39
Define Soilless media:
Sand. Heavy, few nutrient with no buffering capacity and no cation exchange capacity (CEC). Used usually with organic materials. Fine sand keeps things too wet and anoxic. Coarse sand better than fine sand for rooting in cuttings
40
Define Peat moss:
Remains of aquatic, marsh or swamp vegetation which is preserved under water in partially decomposed state. Holds 15-20% dry weight in water. Acid pH (3.2 - 4.5), small amount of Nitrogen. Comprises 70-80 % of many commercial mixes. Darker is more decomposed. Peat is hard to wet, so wetting agents are used.
41
Define Compost :
organic matter that has been decomposed in a process called composting.
42
Define Perlite:
It is a light gray/white mined silica from volcanic origin. Extremely light in weight. Holds 3-4 times water comparing to its weight. Common rooting medium when mixed with peat or other organic material.
43
Define Vermiculite:
It is mica based hydrated magnesium, aluminum, iron silicate mineral material which expands significantly on heating. It has very light weight, high CEC and holds a lot of water. Usually comes sterile.
44
Define Propagation containers:
container used to propagate plants. Can be Flats, Clay pots, Plastic pots, Fiber pots, Peat, fiber, rockwoolblocks
45
What is the difference between soilless and soil media?
- The soilless media is heavy, have few nutrient with no buffering capacity and no cation exchange capacity (CEC). While the soil media is the contrary.
46
List types of protected housed in a nursery
Greenhouses, polyhouses, lathhouses
47
Why plastic houses are more commonly used in North America?
- Plastic is less expensive than glass
- Support frames are cheaper and lighter for poly structures.
- Cannot use other type of greenhouse because of winter cold.
48
What is the difference between pasteurization and sterilization?
- Pasteurization kills bacteria by using heat while sterilization kill all the microorganisms and their spores.
49
What are the characteristics of ideal media for growing nursery plants?
- Firm to hold the plant
- Constant volume under wet/dry condition
- should be porous for drainage/moisture and aeration.
- free from weed seeds, nematodes
- neutral pH level - depending on plant species.
50
Compare some of the features of containers used for greenhouse-grown plants
- Seedling flats: transparent plastic covers to keep the humidity high. Ventilation is important on warm days.
- Jiffy pellets: rehydrated in water to make a type of peat pot.
- Rockwool: hydroponic greenhouse industry. Made of melted basalt spun into fiber.
51
Define Genotype:
is the set of genes that it carries.
52
Define Phenotype:
is all of its observable characteristics
53
Define Cell division:
the division of a cell into two daughter cells with the same genetic material.
54
Define Mitosis:
produces two daughter cells with the same genetic component as the parent cell.
55
Define Meiosis:
produces haploid sex cells or gametes (single copy of each chromosome) from diploid cells contain two copies of each chromosome).
56
Define Sites of mitosis:
Meristematic sites (normal growth)
57
Define Apical meristem:
Shoot and root apex
58
Define Axillary meristem:
Axillary (lateral) buds
59
Define Intercalary zones:
Common in grasses, at the base of internodes.
60
Define Lateral meristem:
run parallel to the long axis of a plant (growth in diameter).
61
Define Vascular (bundle) cambium:
produces secondary growth of xylem, phloem
62
Define Adventitious organ:
appear in an unusual place or at an unusual time.
63
Define Species:
is an individual plant with specific characteristics. retain their distinctions through successive generations.
64
Define Cultivar:
is a contraction for cultivated variety, a group of plants with unique characteristics; usually with a name.
It is an assemblage of cultivated plants distinguishing by any characters (morphological, physiological, cytological, chemical, etc.) and when reproduced (either sexually or asexually, depending on the plant) retains its distinguishing characters.
65
Define Cline:
is a gradient in a measurable characteristic following environmental gradients.
66
Define Ecotype:
a group of plants that have similar genotype living in specific environmental condition.
67
What do you know about geographical and temporal barriers?
Temporal barriers
o Different timing for pollen production
o Fertilization (receptive stigma).
o Plant Propagator's Solution - collect and preserve the pollen then fertilize directly or fertilize later.
Geographical barriers
o Species not in the same geographic regions
68
What is the difference between a cultivar and species?
A cultivar is a variant produced by humans, by crossing natural species and favoring those with some desired trait. A species is a variant that evolves naturally from related forebears, surviving and eventually stablilizing because it is better adapted to its environs
69
What is the correct way of writing cultivar names?
- The name must include the genus and species (sp.) name, (these must be underlined or Italicized) and followed by cv. and the cultivar name, or the cultivar name is enclosed in ‘single quotation marks’.
- Interspecific hybrids have an “x” in their name.
- Intergeneric hybrids have an “x” before their name.
70
What are the main classes of Angiosperms?
- Monocotyledons (palms, orchids, grasses, etc.)
| - Dicotyledons (apples, peas, carrots, etc.).
71
Define Annual:
Flowering, seed production, and dissemination occurs during a single growing season, followed by plant death.
72
Define Biennial:
Plants with a 2-growing season life cycle, vegetative the first year and reproductive the following year. Winter in between for obligatory cold (vernalization).
73
Define Perennial:
Plants live for more than 2 years with an annual cycle of vegetative and reproductive growth.
74
Define Juvenile phase:
Vegetative growth predominates. Plant is non reproductive, and cannot respond to flower-inducing stimuli.
75
Define Mature phase:
Seasonal growth usually begins with the vegetative stage, in which apical and lateral vegetative buds develop on a shoot, in patterns that are species-dependent. In the second stage, the reproductive stage, some of these vegetative growing points differentiate into flowers and fruit.
76
Define Pollination:
the transfer of pollen from an anther to the stigma in angiosperms or from the microsporangium to the micropyle in gymnosperms
77
Define Fertilization:
is the fusion of gametes to initiate the development of a new individual organism
78
Define Double fertilization:
done in angiosperms. This process involves joining of a female gametophyte with two male gametes. It begins when a pollen grain adheres to the stigma of the carpel, the female reproductive structure of a flower. The pollen grain then takes in moisture and begins to germinate, forming a pollen tube that extends down toward the ovary through the style. The tip of the pollen tube then enters the ovary and penetrates through the micropyle opening in the ovary. The pollen tube proceeds to release the two sperm in the megagametophyte
79
Define Endosperm:
is a tissue produced inside the seeds of most of the flowering plants following fertilization. It is triploid in most species. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein.
80
Define Exine – sporopollenin – intine
Pollen grains have a highly resistant exine (outer wall) made of sporopollenin. The inner wall (intine) made of cellulose and pectin deposited by the pollen cell
81
Define Integument:
the outermost covering of an ovule
82
Define Testa:
is the outermost covering of a seed.
83
Define Plumule:
the primary bud of a plant embryo usually situated at the apex of the hypocotyl and consisting of leaves and an epicotyl
84
Define Radicle:
root of a plant embryo
85
Define Endospermic seeds:
embryo is small relative to the rest of the seed. Storage material is in the endosperm.
86
Define Non-endospermic seeds:
Embryo is dominant (endosperm was used up) and nutrients are stored in the cotyledons.
87
Define Embryogenesis:
morphological and physiological development of the embryo. During this process cell division and expansion are occurring in various areas of the embryo.
88
Define Vivipary:
the development of vegetative shoots upon or among the reproductive organs of a plant. Seed germinating in the fruit. Eg: tomato
89
Define Parthenocarpy:
fruit development without pollination and fertilization of ovule
90
Define Polyembryony:
the seeds having more than one embryo.
91
Define Apomixis:
asexual reproduction involving flowering parts.
92
Define Dormancy:
the inability of living seeds to germinate even with availability of appropriate conditions.
93
Define Primary dormancy:
This is the most common types of dormancy which usually happens during seed maturity on the plant. Primary dormancy occurs as a result of a number of natural and physiological factors which can be: Exogenous dormancy and Endogenous dormancy
94
Define Exogenous dormancy:
Exogenous dormancy: Seed coat dormancy, the seed cover has important role in preventing/inhibiting seeds from germination. This may be due to physical, chemical, mechanical dormancy and impermeability of seed coat to gasses.
95
Define Endogenous dormancy:
It is caused by morphological, physiological or embryonic conditions within the embryo itself.
96
Define Secondary dormancy:
occurs after separating andcollecting seeds from mother plants. This happens due to the effect of seed coat or chemical growth inhibitors and other factors influenced by environment.
97
Define Stratification:
Washing Seeds, combination of treatments (use more than one treatment), Alternation of seeds to daily temperature, Exposing seeds to light, Hormones and growth regulators and stimulants.
98
Define Scarification:
Mechanical scarification or scratching, Chemical scarification (sulfuric acid, potassium nitrate, sodium hypochlorite), Hot water scarification (Immersion in hot water), Thermal scarification (high temperature treatment)
99
What is the main component of outer layer of a pollen grain?
- Pollen grains have a highly resistant exine (outer wall) made of sporopollenin.
100
What are the parts of Anther and describe the compound that covers the polling grain?
- The anther has 4 pollen sacs
- Each contains nutritive tissue (tapetum) to feed developing microspores.
- Pollen grains have a highly resistant exine (outer wall) made of sporopollenin.
101
Which part of flower becomes fruit?
- Carpels
102
Does it have any advantage in plant propagation?
- For advantage, mangrove have an advantage in propagation because vivipary helps it to propagate
103
Define Landrace:
populations of locally adapted plants
104
Define Cross pollination:
pollen comes from a different plant or clone.
105
Define Self-pollination:
Pollen comes from the same flower or different flowers on the plant, or flowers on other plants of the same clone.
106
Define Single cross:
inbred line x inbred line
107
Define Double cross:
single cross x single cross
108
Define true-breeding line:
A group of genetically identical homozygous individuals that, when intercrossed, produce only offspring that are identical to their parents.
109
Define Pure-line cultivars:
all plants in the population (theoretically) come from a single Define true-breeding (essentially homozygous) plant.
110
Define Multi-line cultivars:
are a mixture of genetically different lines.
111
Define Synthetic cultivar:
genetically distinct but phenotypically similar lines or clones are randomly crossed.
112
Define Variety registration:
Some crops are registered based on merit (cereals, forages, field corn, potato, etc.). A new variety of these crops must be equal to or better than existing cultivars.
113
Define Certified seed:
seed that has passed field inspection and seed testing standards for varietal purity, which is the absence of certain wheat and other crop seeds, and certain diseases.
114
Define Composite cultivar:
is a cultivar that can be maintained indefinitely like this.
115
Define Plus trees:
A tree selected on the basis of its outstanding phenotype but not yet clonally or progeny tested.
116
Define Elite trees:
Trees that produce desirable progeny
117
Define Pure stand:
a plant population consisting exclusively or largely of members of one species, variety, or type
118
Define Progeny test:
a test of the value for selective breeding of an individual's genotype by looking at the progeny produced by different matings.
119
Define Seed collection zone:
defined area, known ecotype, given a numbered code.
120
Define Seed orchard:
the trees are of proven genetic superiority defined by a certifying agency (elite) and cross-pollination is encouraged.
121
Define Select seed:
This is produced by recognized experienced seed growers (select seed growers) in small plots. Can be derived from Breeder’s seed.
122
Seeds are used to propagate which kind of plants?
- Most annual and biennial agronomic crops,
- Vegetable crops,
- Many garden and floral species,
- Some ornamental herbaceous perennials,
- Many woody landscape tree species,
- Forest trees and shrubs.
123
What are classes for commercial seed production in Canada?
Development Phase of Seed Production
o Breeder's seed - A small amount of seed is produced by plants carefully selected by the plant breeder as representing a new cultivar. It could take a breeder 10 years to get to this point.
o Not for resale - used to show "type".
Maintenance Phase of Seed Production
o Select seed: This is produced by recognized experienced seed growers (select seed growers) in small plots. Can be derived from Breeder's seed.
o Several generations of select seed may be permitted. This parental seed is not for commercial sale it is just to maintain the seed.
o Select seed (Canada) is the equivalent to Foundation seed used in (U.S.).
Multiplication and Distribution Phase of Seed Production
o Registered seed: Produced from Select seed. Grown under specific, approved conditions by Select seed growers.
o Certified seed: Produced in the largest volume and sold to the commercial growers.
124
Why seeds are tested and Inspected?
- Maintain genetic identity of plant cultivars.
- Prevent contamination by cross-pollination with other cultivars
- Prevent mixing during harvest.
125
Where do farmers get their seeds?
- Collect it (wild, seed orchards, previous crop)
- Buy it from commercial seed sources; for example seed production industries (agricultural, vegetable, and flower seeds), seed collecting firms (woody plant seed), seed exchanges of arboreta and plant societies.
- Obtain it from fruit processing industries.
126
How is variety registration done in Canada?
- Varieties are registered by the Variety Registration Office of the Canadian Food Inspection Agency (CFIA) of Agriculture and Agri-Food Canada (AAFC). Some crops are registered based on merit (cereals, forages, field corn, potato, etc.). A new variety of these crops must be equal to or better than existing cultivars.
127
What seed sources could be used for woody perennial species?
- may be taken from specialized seed orchards or from natural populations.
- Local seed or seed from a known provenance that matches the growing area.
- A seed collection zone = defined area, known ecotype, given a numbered code.
128
What are types of seed orchards?
- Seedling trees from selected parents through controlled or natural pollination.
- Clonal seed orchards - clones are propagated by grafting, budding, rooting cuttings.
- Seedling-clonal seed orchards where certain clones are grafted onto branches of some of the trees.
129
What are methods of seed viability determination?
Direct germination - optimum environmental conditions
o First count at 1 week, discard, count weekly for weeks (species specific).
o Test terminated and all non-germinated seeds critically examined.
o Divided into categories = normal germination, abnormal, dead/decayed seeds, dormant seeds, hard (non-imbibed) seeds.
o At least four batches of 100 seeds are used.
o If the results correlate within 10% the average is taken as the germination %.
o If not the test is repeated.
Excised embryo test - embryo removed from its seed coat (in some cases also from the endosperm).
o Embryo onto moist substrate in a Petri dish.
o Non-viable embryos decay in 2-10 days.
o Viable embryos spread their cotyledons, grow or become green.
Tetrazolium test - dehydrogenase enzymes turn 2,3,4- triphenyltetrazolium (TTC) to red, insoluble formazan in both dormant and non-dormant imbibed seeds.
o Usually 0.1-1.0% TTC is used, pH 6-7 and exposure is 2-24 hours.
o You may do this in the lab
130
How verification of genotype can be done?
- Visual examination usually is used to determine "trueness to type". A field or greenhouse grow-out test might be required to distinguish characteristics of flowering or maturity.
- Chromosome counts are useful to check ploidy levels or where specific chromosome differences can be observed microscopically.
- Electrophoresis, chromatography may be useful for distinguishing genotypes based on protein or isoenzyme banding patterns (fingerprinting).
- DNA analysis (RFLP, RAPDs) can be used for cultivar identification and fingerprinting. This is becoming more and more common.
- Chemical and u.v. tests - Differential staining in phenol solution (1% carbolic acid) or different fluorescence under u.v. are diagnostic of cultivars.
131
What are Harrington's rules of thumb for seed storage and longevity?
At 5 to 14% moisture, each 1% decrease in seed moisture doubles seed life.
- At 0 to 50 C, each 5C decrease in temperature doubles seed life.
132
What are types of seed storage?
Unregulated open storage
o No moisture or temperature control used.
o For many orthodox seeds, to hold seeds from one
o season to the next.
o No special conditions required for very long-lived seeds with impermeable seed coats
Conditioned storage
o Includes dehumidified and/or refrigerated facilities (< 10 C and RH 50-70%).
o Expensive.
o Valuable seeds (e.g. breeding stock).
o Necessary in the humid tropics.
Moist cool storage
o Temp 0-10 C, at RH 80-90% is similar to stratification (moist chilling) conditions.
133
Define Germination:
an organism grows from a seed or similar structure. Reactivation of the cells' metabolic machinery.
134
Define Hypogeous:
below the soil. The cotyledons of the germinating seed remain non-photosynthetic, inside the seed shell, and below ground
135
Define Epigeous:
above the soil. The cotyledons of the germinating seed expand, throw off the seed shell and become photosynthetic above the ground.
136
Define Phytochrome:
a class of photoreceptor in plants, bacteria and fungi used to detect light. Photochemically reactive pigment. Responsive at the red end of the spectrum. Effects are immediate, reversible, and repeatable.
137
Define Red and far red light:
related to phytochrome
138
Define Photodormancy:
Seed that either require light or dark conditions to germinate
139
Define Thermodormancy:
Germination at high temperatures (>25°C or 77°F) can induce thermo-dormancy.
140
Define Cytokinin:
important for controlling cell division in plants. Promote shoot formation in tissue cultures. High in developing fruits and seeds. Decrease during seed maturation. These can counteract ABA.
141
Define Gibberellin:
occur in high concentrations in developing seeds and have important functions in germination and control of dormancy. occur in high levels in shoot meristems and promote stem elongation by stimulating cell division and elongation. Dwarf plants are usually impaired for gibberellin biosynthesis or perception. Increase during chilling (stratification)
142
Define Abscisic acid:
involved in control of dormancy in buds and seeds. ABA also regulates stomatal closure during water stress. In germination and dormancy of seeds and plays a role in the embryogenesis and production of seeds.
143
Define Ethylene:
Promotes germination of some seeds
144
What are stages of seed germination?
Stage I
o Imbibition of water:
seed coat softens, protoplasm of cells hydrates, seed swells, seed coat may split.
Early imbibition = physical process Can occur even in dead seeds.
o Lag phase:
Enzymes present in seeds, reactivated by hydration.
2 - 4 hours for new enzyme synthesis from stored mRNA and amino acids.
6 - 12 hours for new enzyme synthesis from new mRNA using amino acids derived from degradation of stored proteins.
Stored ATP for this process is also reactivated by cell hydration.
o The radicle emerges (chitting)
Cells elongate due to hydration, not cell division
Takes a few hours.
Stage 2
o Digestion and Translocation
Stored food is digested and moved to embryo growing points.
Specific enzymes activate in sequence. Water uptake and respiration continue.
Stage 3
o Seedling Growth
Storage tissues no longer involved (except photosynthetic cotyledons)
Seedling becomes photoautotrophic.
Plant rapidly accumulates dry matter, synthesizes everything and grows.
145
Write briefly on environmental factors affecting seed germination
- Water
- ~40-60% water on a fresh weight basis require for germination.
- More water needed when leaching of inhibitors is required.
- Too much water causes anoxia, disease.
146
List some of germination promoters and inhibitors
```
Promotors
o red light
o oxygen
o GA3
o cytokinins
o water
o ethylene
o moderate-low temperature
o (<20 C)
Inhibitor
o far red light
o ABA
o moisture stress
o high temperature
o CO2
```
147
Define Vegetative propagation:
based on the property of totipotency; the ability of individual somatic or plant body cells to reconstitute an entire plant.
148
Define Cloning:
is vegetative propagation
149
Define Periphysis:
is the carry-over effect of environment on the plants or on propagules from these plants without permanent genetic change.
150
Define Cyclophysis:
The procesis of maturation of the apical meristems.
151
Define Topophysis:
Phenomenon in which cuttings from a certain portion of a plant maintain the same phase as the part from which the cutting was taken.
152
Define Prostrate shoot:
is plagiotropic. Growing at an oblique or almost horizontal angle
153
Define Upright shoot:
is orthotropic. Growing vertically, either upwards or downwards.
154
Define Epigenetic changes:
Concept explains phase change control mechanisms.
155
Define Physiological changes:
changes do not persist when the stimulus ends.
156
Define Regeneration:
The major juvenile feature. Continued pruning can arrest plants in the juvenile phase. Very good for continued propagation. Speed up flowering of some plants by manipulating water, light, fertilizer, etc.
157
Define Reversion:
from adult to juvenile phase occurs naturally with sexual reproduction and formation of the embryo and seedling plant.Reversions from adult to juvenile phase can be done experimentally by Tissue culture systems, GA3 treatment, Successive grafting to juvenile tissue (grape, ivy, eucalyptus, etc.).
158
Define Mutation :
Can affect the nuclear chromosomes of plants (aneuploidy, polyploidy) or the genomes either of the plastids (chloroplasts) or mitochondria. Conspicuous (easy to see) mutations involving the chloroplasts = loss of chlorophyll leads to variegated (mixed colors) or albino (white) plants.
159
Define Chimera :
Mutation can occur in the meristematic cells of a bud. Can eventually affect the whole plant branch which could include the fruit. Called a bud sport or bud mutation Can be deleterious or wonderful (pink!grapefruit in an orchard of white ones). A plant like this with more than one kind of genetic tissue is called a chimera.
160
Define Somaclonal Variation :
Variation seen in individual plants regenerated from cells growing in tissue culture. May have value to plant breeders.
161
What are advantages and disadvantages of vegetative propagation?
Advantages
o Exploiting superior genotypes
o Work with highly uniform phenotypes
o Big genetic advance over some seedling populations
o Ie : uniform growth, ripening time, shortened time to flowering/fruiting.
Disadvantages
o Potential for variation via selection of inferior variant plant.
o Decline due to disease, pathogens, improper handling.
o Select one genotype to perpetuate; so less useful genotypes may be eliminated = net loss of genetic diversity.
162
What do homoblastic and heteroblastic mean?
- Homo: phases are not distinct in appearance
| - Hetero: phases are distinct in appearance (can visually observe them)
163
What is the cone of juvenility?
- The juvenile to mature gradient in seedling trees
164
Is it possible to see all phases changes in the same plant? Explain briefly
- Yes in trees.
165
What is technique or method of maintaining plants in juvenile phase?
- topophysis
166
What are sources of genetic variation in asexually propagated plants?
- Mutation
- Chimeras
- Somaclonal variation
167
Define Plantlets:
shoots and roots from primary meristems. These have never ceased their meristematic activity but have become latent.
168
Define Leaf blade:
the leaf
169
Define Petiole:
is the stalk that attaches the leaf blade to the stem.
170
Define Foliar embryo:
the embryo developed from the leaf.
171
Define Wounding:
the process of removing some of the outer layer of stem or the bark covering the cambium, so that this layer is visible.
172
Define Callus:
a hard formation of tissue, especially new tissue formed over a wound.
173
Define Abaxial:
bottom of leaf
174
Define Adaxial:
top of leaf
175
Define Leaf disk:
making disk of leaf for propagation
